Numerical simulations of transient-stage Ostwald ripening and coalescence in two dimensions

A new numerical method for tracking interface motion in microstructures is described and used to simulate two-dimensional, transient-stage Ostwald ripening at high volume fractions of coarsening phase. Two limiting kinetic regimes are explicitly simulated, namely diffusion-controlled mass transport and surface-attachment/detachment-limited kinetics (SALK). The simulations indicate important qualitative and quantitative differences between these two mechanisms at high volume fractions. These differences include: (1) The persistence of coalescence events under SALK that are completely absent under diffusion control; and (2) stable circular shapes for isolated domains under SALK; under diffusion control, the morphology of an isolated domain is dependent on its nearby surroundings, as reported by other investigators. Spatial correlations amongst the coarsening domains are also investigated using two-point correlation functions and medium polarization functions.